Flush buffer after forming archive

Data remains in the GzEncoder. Ensure it is flushed before performing
any other operations on the tarball.

This fixes a bug in the report generation, where the tarball of the raw
data is copied to data/archive/. When trying to untar the file, the data
is corrupted and unuseable.

src/lib.rs

@@ -12,6 +12,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::{self};
 use std::collections::HashMap;
 use std::{fs, time};
+use std::io::Write;
 use std::path::Path;
 use std::sync::Mutex;
 use thiserror::Error;
@@ -209,6 +210,7 @@ impl PerformanceData {
         let enc = GzEncoder::new(tar_gz, Compression::default());
         let mut tar = tar::Builder::new(enc);
         tar.append_dir_all(&dir_name, &self.init_params.dir_name)?;
+        tar.into_inner()?.flush()?;
         info!("Data collected in {}/, archived in {}", self.init_params.dir_name, archive_path);
         Ok(())
     }

src/report.rs

@@ -47,6 +47,7 @@ pub fn form_and_copy_archive(loc: String, report_name: &PathBuf) -> Result<()> {
         let enc = GzEncoder::new(tar_gz, Compression::default());
         let mut tar = tar::Builder::new(enc);
         tar.append_dir_all(&dir_stem, &loc)?;
+        tar.into_inner()?.flush()?;
 
         /* Copy archive to aperf_report */
         let archive_dst = report_name.join(format!("data/archive/{}", archive_name));
@@ -227,6 +228,7 @@ pub fn report(report: &Report) -> Result<()> {
     let enc = GzEncoder::new(tar_gz, Compression::default());
     let mut tar = tar::Builder::new(enc);
     tar.append_dir_all(&report_name, &report_name)?;
+    tar.into_inner()?.flush()?;
     fs::remove_dir_all(APERF_TMP)?;
     Ok(())
 }